Usefulness of EQ-5D for evaluation of health-related quality of life in young adults with first-episode psychosis

Time perspective profile and self-reported health on the EQ-5D

OBJECTIVES

Time perspective (TP) is a psychological construct that is associated with several health-related behaviours, including healthy eating, smoking and adherence to medications. In this study, we aimed to examine the associations of TP profile with self-reported health on the EQ-5D-5L and to detect which domains display response heterogeneity (cut-point shift) for TP.

METHODS

We conducted a secondary analysis of EQ-5D-5L data from a representative general population sample in Hungary (n = 996). The 17-item Zimbardo Time Perspective Inventory was used to measure individuals' TP on five subscales: past-negative, past-positive, present-fatalist, present-hedonist and future. The associations between TP subscales and EQ-5D-5L domain scores, EQ VAS and EQ-5D-5L index values were analysed by using partial proportional odds models and multivariate linear regressions.

RESULTS

Respondents that scored higher on the past-negative and present-fatalist and lower on the present-hedonist and future subscales were more likely to report more health problems in at least one EQ-5D-5L domain (p < 0.05). Adjusting for socio-economic and health status, three EQ-5D-5L domains exhibited significant associations with various TP subscales (usual activities: present-fatalist and future, pain/discomfort: past-negative and future, anxiety/depression: past-negative, present-fatalist, present-hedonist and future). The anxiety/depression domain showed evidence of cut-point shift.

CONCLUSIONS

This study identified response heterogeneity stemming from psychological characteristics in self-reported health on the EQ-5D-5L. TP seems to play a double role in self-reported health, firstly as affecting underlying health and secondly as a factor influencing one's response behavior. These findings increase our understanding of the non-health-related factors that affect self-reported health on standardized health status measures.

An Investigation of Age-Related Differential Item Functioning in the EQ-5D-5L Using Item Response Theory and Logistic Regression

OBJECTIVES

In economic evaluations, quality of life is measured using patient-reported outcome measures (PROMs), such as the EQ-5D-5L. A key assumption for the validity of PROMs data is measurement invariance, which requires that PROM items and response options are interpreted the same across respondents. If measurement invariance is violated, PROMs exhibit differential item functioning (DIF), whereby individuals from different groups with the same underlying health respond differently, potentially biasing scores. One important group of healthcare consumers who have been shown to have different views or priorities over health is older adults. This study investigates age-related DIF in the EQ-5D-5L using item response theory (IRT) and ordinal logistic regression approaches.

METHODS

Multiple-group IRT models were used to investigate DIF, by assessing whether older adults aged 65+ years and younger adults aged 18 to 64 years with the same underlying health had different IRT parameter estimates and expected item and EQ-5D-5L level sum scores. Ordinal logistic regression was also used to examine whether DIF resulted in meaningful differences in expected EQ level sum scores. Effect sizes examined whether DIF indicated meaningful score differences.

RESULTS

The anxiety/depression item exhibited meaningful DIF in both approaches, with older adults less likely to report problems. Pain/discomfort and mobility exhibited DIF to a lesser extent.

CONCLUSIONS

When using the EQ-5D-5L to evaluate interventions and make resource allocation decisions, scoring bias due to DIF should be controlled for to prevent inefficient service provision, where the most cost-effective services are not provided, which could be detrimental to patients and the efficiency of health budgets.

Treating common mental disorder including psychotic experiences in the primary care improving access to psychological therapies programme (the TYPPEX study): protocol for a stepped wedge cluster randomised controlled trial with nested economic and process evaluation of a training package for therapists

INTRODUCTION

At least one in four people treated by the primary care improving access to psychological therapies (IAPT) programme in England experiences distressing psychotic experiences (PE) in addition to common mental disorder (CMD). These individuals are less likely to achieve recovery. IAPT services do not routinely screen for nor offer specific treatments for CMD including PE. The Tailoring evidence-based psychological therapY for People with common mental disorder including Psychotic EXperiences study will evaluate the clinical and cost-effectiveness of an enhanced training for cognitive behavioural therapists that aims to address this clinical gap.

METHODS AND ANALYSIS

This is a multisite, stepped-wedge cluster randomised controlled trial. The setting will be IAPT services within three mental health trusts. The participants will be (1) 56-80 qualified IAPT cognitive behavioural therapists and (2) 600 service users who are triaged as appropriate for cognitive behavioural therapy in an IAPT service and have PE according to the Community Assessment of Psychic Experiences-Positive 15-items Scale. IAPT therapists will be grouped into eight study clusters subsequently randomised to the control-intervention sequence. We will obtain pseudonymous clinical outcome data from IAPT clinical records for eligible service users. We will invite service users to complete health economic measures at baseline, 3, 6, 9 and 12-month follow-up. The primary outcome will be the proportion of patients with common mental disorder psychotic experiences who have recovered by the end of treatment as measured by the official IAPT measure for recovery.

ETHICS AND DISSEMINATION

The study received the following approvals: South Central-Berkshire Research Ethics Committee on 28 April 2020 (REC reference 20/SC/0135) and Health Research Authority (HRA) on 23 June 2020. An amendment was approved by the Ethics Committee on 01 October 2020 and HRA on 27 October 2020. Results will be made available to patients and the public, the funders, stakeholders in the IAPT services and other researchers.

TRIAL REGISTRATION NUMBER

ISRCTN93895792.

Psychometric properties of the EQ-5D-5L in patients with major depression: factor analysis and Rasch analysis

BACKGROUND

The EQ-5D is one of the most recommended questionnaires for cost-effectiveness studies.

AIMS

To study the psychometric properties of the EQ-5D-5L in patients with major depression.

METHODS

This prospective observational study included 433 patients with major depression who completed the EQ-5D-5L and Patient Health Questionnaire-9 (PHQ-9) questionnaires at baseline, of whom 310 also did six months later. The structural validity was assessed by confirmatory factor analysis, the item functioning by item response analysis, and reliability by Cronbach's alpha. Convergent validity and known-groups validity was studied using the PHQ-9 and a general health question. To assess responsiveness effect sizes were calculated.

RESULTS

The results supported the unidimensionality and showed adequate item functioning, with somewhat age-related item differential functioning for the mobility dimension. Cronbach's alpha was 0.77. The EQ-5D-5L showed a high correlation with the PHQ-9 and general health. The more severe the depression level and the poorer the general health, the lower the EQ-5D-5L scores (p < 0.001). Responsiveness parameters showed moderate changes among "improved" patients.

CONCLUSIONS

These findings support the adequate psychometric properties of the EQ-5D-5L in patients with major depression. It could be very useful for clinicians and researchers as an outcome measure and for use in economic evaluation.

Psychometric properties of Short Form-36 Health Survey, EuroQol 5-dimensions, and Hospital Anxiety and Depression Scale in patients with chronic pain

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This large-sample item response theory-based evaluation assessed the measurement properties of SF-36, EQ-5D, and hospital anxiety and depression scale for chronic pain patients in clinical settings.

Recent research has highlighted a need for the psychometric evaluation of instruments targeting core domains of the pain experience in chronic pain populations. In this study, the measurement properties of Short Form-36 Health Survey (SF-36),EuroQol 5-dimensions (EQ-5D) and Hospital Anxiety and Depression Scale (HADS) were analyzed within the item response-theory framework based on data from 35,908 patients. To assess the structural validity of these instruments, the empirical representations of several conceptually substantiated latent structures were compared in a cross-validation procedure. The most structurally sound representations were selected from each questionnaire and their internal consistency reliability computed as a summary of their precision. Finally, questionnaire scores were correlated with each other to evaluate their convergent and discriminant validity. Our results supported that SF-36 is an acceptable measure of 2 independent constructs of physical and mental health. By contrast, although the approach to summarize the health-related quality of life construct of EQ-5D as a unidimensional score was valid, its low reliability rendered practical model implementation of doubtful utility. Finally, rather than being separated into 2 subscales of anxiety and depression, HADS was a valid and reliable measure of overall emotional distress. In support of convergent and discriminant validity, correlations between questionnaires showed that theoretically similar traits were highly associated, whereas unrelated traits were not. Our models can be applied to score SF-36 and HADS in chronic pain patients, but we recommend against using the EQ-5D model due to its low reliability. These results are useful for researchers and clinicians involved in chronic pain populations because questionnaires' properties determine their discriminating ability in patient status assessment.

Model Selection of Nested and Non-Nested Item Response Models Using Vuong Tests

In this paper, we apply Vuong's general approach of model selection to the comparison of nested and non-nested unidimensional and multidimensional item response theory (IRT) models. Vuong's approach of model selection is useful because it allows for formal statistical tests of both nested and non-nested models. However, only the test of non-nested models has been applied in the context of IRT models to date. After summarizing the statistical theory underlying the tests, we investigate the performance of all three distinct Vuong tests in the context of IRT models using simulation studies and real data. In the non-nested case we observed that the tests can reliably distinguish between the graded response model and the generalized partial credit model. In the nested case, we observed that the tests typically perform as well as or sometimes better than the traditional likelihood ratio test. Based on these results, we argue that Vuong's approach provides a useful set of tools for researchers and practitioners to effectively compare competing nested and non-nested IRT models.

Assessing quality of life in psychosocial and mental health disorders in children: a comprehensive overview and appraisal of generic health related quality of life measures

BACKGROUND

Mental health problems often arise in childhood and adolescence and can have detrimental effects on people's quality of life (QoL). Therefore, it is of great importance for clinicians, policymakers and researchers to adequately measure QoL in children. With this review, we aim to provide an overview of existing generic measures of QoL suitable for economic evaluations in children with mental health problems.

METHODS

First, we undertook a meta-review of QoL instruments in which we identified all relevant instruments. Next, we performed a systematic review of the psychometric properties of the identified instruments. Lastly, the results were summarized in a decision tree.

RESULTS

This review provides an overview of these 22 generic instruments available to measure QoL in children with psychosocial and or mental health problems and their psychometric properties. A systematic search into the psychometric quality of these instruments found 195 suitable papers, of which 30 assessed psychometric quality in child and adolescent mental health.

CONCLUSIONS

We found that none of the instruments was perfect for use in economic evaluation of child and adolescent mental health care as all instruments had disadvantages, ranging from lack of psychometric research, no proxy version, not being suitable for young children, no age-specific value set for children under 18, to insufficient focus on relevant domains (e.g. social and emotional domains).

A Differential Item Functioning Analysis of the EQ-5D in Cancer

OBJECTIVES

To determine whether differential item functioning (DIF) was present in the EuroQol five-dimensional questionnaire (EQ-5D) used in cancer (non-small cell lung cancer and prostate cancer).

METHODS

The Partial Credit Model was applied to the three-level version of the EQ-5D with data obtained from four randomized controlled trials in prostate cancer and non-small cell lung cancer completed at baseline before treatment (N = 2213). DIF was assessed across cancer type (two levels), sex (two levels), and age group (three levels) using Mantel-Haenszel chi-square statistics and evaluated against the Educational Testing Service classification rules.

RESULTS

The presence of DIF was determined in 14 of 25 (56%) potential DIF contrasts in all the EQ-5D domains. Although mostly the DIF was categorized as either negligible (3 of 25 [12%]) or medium (7 of 25 [28%]), large DIF was observed in 4 of the 25 contrasts (16%). The mobility domain, in particular, showed consistently large DIF across cancer type, sex, and age.

CONCLUSIONS

Given the use of the instrument in health status assessments across conditions and interventions, these results may have significant implications for the EQ-5D in health economic evaluations. Further research is warranted to determine whether these results hold for other cancers.

Pain is independently associated with reduced health related quality of life in people with psychosis

The objective was to investigate the relationship between pain and health related quality of life (HRQOL) in people with psychosis. The study utilised a cross-sectional design including individuals with established psychosis from five Mental Health Trusts across England. Participants were classified as having pain or not and HRQOL was determined with the EQ-5D-3L. Covariates considered include the Positive and Negative Syndrome Scale (PANSS), the Montgomery Asberg Depression Rating Scale (MADRS) and Global Assessment of Functioning (GAF). Hierarchical multiple linear regression analyses were conducted. The final sample included 438 individuals with psychosis (47.5 years, SD 10.1, 193 females (42.9%)). 160 participants reported pain (36.5%) and compared to the non-pain group (N=278) they had significantly higher depressive symptoms (MADRS 14.91 vs 8.68), total (51.8 vs 47.9) and general PANSS scores (26.8 vs. 23.5) and lower overall HRQOL (54.7 vs 68.3). The final regression analysis (n=387) demonstrated that lower levels of pain were a predictor of better HRQOL (β=.173) after adjusting for the PANSS, MADRS and GAF. Depressive symptoms were the largest predictor of HRQOL (β=-.486). Only 1-2% of the sample were in receipt of analgesic medication suggesting pain is greatly overlooked despite its wider deleterious impact on HRQOL.

EQ-5D as a measure of programme outcome: results from the Singapore early psychosis intervention programme

The current study aimed to establish the Health-Related Quality of Life (HRQoL) among participants with First Episode Psychosis (FEP) in Singapore, to elucidate the sociodemographic and clinical correlates of HRQoL, and ascertain the change after 1-year of treatment. Two hundred and forty one patients accepted into an Early Psychosis Intervention Programme (EPIP) from April 2009 to June 2011 and who had completed baseline EuroQol-5D (EQ-5D) assessments were included in this analysis. The mean (S.D.) EQ-5D index at baseline was 0.788 (0.258). One hundred thirty five (56.0%) patients who completed the EQ-5D assessment at the 12-month follow-up had a significantly higher EQ-5D index as compared to baseline. EQ-5D index was significantly higher among those patients who met criteria for remission at the 12-month interval than those who were not in remission. Our results suggest that the EQ-5D is responsive to improvement as it corresponded well to objective ratings of remission in our patients with FEP.

Development, validity and reliability of the short multidimensional positive mental health instrument

PURPOSE

The 47-item positive mental health (PMH) instrument measures the level of PMH in multiethnic adult Asian populations. This study aimed to (1) develop a short PMH instrument and (2) establish its validity and reliability among the adult Singapore population.

METHODS

Two separate studies were conducted among adult community-dwelling Singapore residents of Chinese, Malay or Indian ethnicity where participants completed self-administered questionnaires. In the first study, secondary data analysis was conducted using confirmatory factor analysis (CFA) to shorten the PMH instrument. In the second study, the newly developed short PMH instrument and other scales were administered to 201 residents to establish its factor structure, validity and reliability.

RESULTS

A 20-item short PMH instrument fulfilling a higher-order six-factor structure was developed following secondary analysis. The mean age of the participants in the second study was 41 years and about 53% were women. One item with poor factor loading was further removed to generate a 19-item version of the PMH instrument. CFA demonstrated a first-order six-factor model of the short PMH instrument. The PMH-19 instrument and its subscales fulfilled criterion validity hypotheses. Internal consistency and test-retest reliability of the PMH-19 instrument were high (Cronbach's α coefficient = 0.87; intraclass correlation coefficient = 0.93, respectively).

CONCLUSIONS

The 19-item PMH instrument is multidimensional, valid and reliable, and most importantly, with its reduced administration time, the short PMH instrument can be used to measure and evaluate PMH in Asian communities.